Virtual multicarrier design for orthogonal frequency division multiple access communications

ABSTRACT

Embodiments of the present invention provide a virtual multicarrier design for orthogonal frequency division multiple access communications. Other embodiments may be described and claimed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/658,735, filed Oct. 23, 2012, entitled, “VIRTUALMULTICARRIER DESIGN FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESSCOMMUNICATIONS,” which is a continuation of U.S. patent application Ser.No. 12/242,755 filed Sep. 30, 2008, entitled, “VIRTUAL MULTICARRIERDESIGN FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESSCOMMUNICATIONS,” the entire specification of which is herebyincorporated by reference in its entirety for all purposes.

FIELD

Embodiments of the present disclosure relate to the field of wirelessaccess networks, and more particularly, to virtual multicarrier designfor orthogonal frequency division multiple access communications in saidwireless access networks.

BACKGROUND

Orthogonal frequency division multiple access (OFDMA) communications usean orthogonal frequency-division multiplexing (OFDM) digital modulationscheme to deliver information across broadband networks. OFDMA isparticularly suitable for delivering information across wirelessnetworks.

The OFDM digital modulation scheme uses a large number of closely-spacedorthogonal subcarriers to carry information. Each subcarrier is capableof carrying a data stream across a network between OFDMA terminals.

OFDMA-based communication systems are well known to have out of bandemission (OOBE) issues that result in intercarrier interference (ICI).Prior art networks control this ICI by providing guard bands, e.g.,unused subcarriers, between adjacent carriers.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detaileddescription in conjunction with the accompanying drawings. To facilitatethis description, like reference numerals designate like structuralelements. Embodiments are illustrated by way of example and not by wayof limitation in the figures of the accompanying drawings.

FIG. 1 illustrates a wireless communication environment in accordancewith embodiments of this disclosure.

FIG. 2 is a flowchart depicting operations of a base station inaccordance with some embodiments.

FIG. 3 is a flowchart depicting operations of a mobile station inaccordance with some embodiments.

FIG. 4 is a graph illustrating OOBE on two adjacent carriers inaccordance with some embodiments.

FIG. 5 illustrates various views of a configuration of assignedbandwidth in accordance with some embodiments.

FIG. 6 illustrates an OFDMA frame in accordance with some embodiments.

FIG. 7 illustrates a multicarrier transmission being processed with andwithout reuse of guard band subcarriers in accordance with someembodiments.

FIG. 8 illustrates how teachings of various embodiments facilitate aflexible deployment and upgrading of network equipment in accordancewith some embodiments.

FIG. 9 illustrates a computing device capable of implementing a virtualcarrier terminal in accordance with some embodiments.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown by way ofillustration embodiments in which the invention may be practiced. It isto be understood that other embodiments may be utilized and structuralor logical changes may be made without departing from the scope of thepresent invention. Therefore, the following detailed description is notto be taken in a limiting sense, and the scope of embodiments inaccordance with the present invention is defined by the appended claimsand their equivalents.

Various operations may be described as multiple discrete operations inturn, in a manner that may be helpful in understanding embodiments ofthe present invention; however, the order of description should not beconstrued to imply that these operations are order dependent.

For the purposes of the present invention, the phrase “A and/or B” means“(A), (B), or (A and B).” For the purposes of the present invention, thephrase “A, B, and/or C” means “(A), (B), (C), (A and B), (A and C), (Band C), or (A, B and C).”

The description may use the phrases “in an embodiment,” or “inembodiments,” which may each refer to one or more of the same ordifferent embodiments. Furthermore, the terms “comprising,” “including,”“having,” and the like, as used with respect to embodiments of thepresent invention, are synonymous.

Embodiments of the present disclosure describe virtual multicarrierdesigns for OFDMA communications as may be used by multicarriertransmission schemes presented in, e.g., the Institute of Electrical andElectronics Engineers (IEEE) 802.16—2004 standard along with anyamendments, updates, and/or revisions (e.g., 802.16m, which is presentlyat predraft stage), 3^(rd) Generation Partnership Project (3GPP)long-term evolution (LTE) project, ultra mobile broadband (UMB) project(also referred to as “3GPP2”), etc.

FIG. 1 illustrates a wireless communication environment 100 inaccordance with an embodiment of this disclosure. In this embodiment,the wireless communication environment 100 is shown with three wirelesscommunication terminals, e.g., base station 104, mobile station 108, andmobile station 112, communicatively coupled to one another via anover-the-air (OTA) interface 116.

In various embodiments, the mobile stations 108 and 112 may be a mobilecomputer, a personal digital assistant, a mobile phone, etc. The basestation 104 may be a fixed device or a mobile device that may providethe mobile stations 108 and 112 with network access. The base station104 may be an access point, a base transceiver station, a radio basestation, a node B, etc.

The wireless communication devices 104, 108, and 112 may have respectiveantenna structures 120, 124, and 128 to facilitate the communicativecoupling. Each of the antenna structures 120, 124, and 128 may have oneor more antennas. An antenna may be a directional or an omnidirectionalantenna, including, e.g., a dipole antenna, a monopole antenna, a patchantenna, a loop antenna, a microstrip antenna or any other type ofantenna suitable for transmission/reception of radio frequency (RF)signals.

Briefly, the base station 104 may have a baseband processing block (BPB)132 coupled to a transmitter 136. The BPB 132 may be configured toencode input data, which may be received in a binary format, as an OFDMsignal on logical subcarriers of a virtual carrier. The logicalsubcarriers may be mapped to physical subcarriers from at least twoadjacent physical carriers. The BPB 132 may then control the transmitter136 to transmit the OFDM signal on the physical subcarriers.

FIG. 2 is a flowchart depicting operations of the base station 104 inaccordance with some embodiments. At block 204, an encoder 140 of theBPB 132 may receive input data from upper layers of the base station104.

At block 208, the encoder 140 may encode the input data into frequencydomain OFDM signal having logical subcarriers of a virtual carrier.

At block 212, the encoder 140 may map the logical subcarriers tophysical subcarriers of one or more physical carriers according to amapping scheme provided by the mapper 144.

In some embodiments, the mapping scheme may map indices of the logicalsubcarriers to indices of the physical subcarriers. For example,consider a simple embodiment in which the encoder 140 encodes an OFDMAsignal onto 20 logical subcarriers of a virtual carrier. The logicalsubcarriers may have indices 1-20. A mapping scheme may map the logicalsubcarrier indices 1-20 to physical subcarrier indices 1-5 of a firstphysical carrier, physical subcarrier indices 1-5 of a second physicalcarrier, and physical subcarrier indices 1-10 of a third physicalcarrier. In an actual implementation, the number of subcarriers will besignificantly higher. Furthermore, the total number of logicalsubcarriers need not be equal to the total number of physicalsubcarriers as is described in this example.

The frequency domain OFDM signal may be provided to an inverse fastFourier transformer (IFFT) 148 that transforms the signal into a timedomain OFDM signal, having a plurality of time domain samples forassociated physical subcarriers.

At block 216, the transmitter 136 may be controlled to transmit thephysical subcarriers. The transmitter 136 may provide a variety ofphysical layer processing techniques, e.g., adding cyclic prefix,upconverting, parallel-to-serial conversion, digital-to-analogconversion, etc. to effectuate the transmission.

The receiving process of the mobile stations may operate in a mannerthat complements the transmitting process described above.

FIG. 3 is a flowchart depicting operations of the mobile station 108 inaccordance with some embodiments. At block 304, a receiver 152 of themobile station 108 may receive the physical carriers that carry the OFDMsignal via the OTA interface 116, process the OFDM signal and presentit, as a time domain OFDM signal, to a BPB 156. The complementaryphysical layer processing techniques of the receiver 152 may include,e.g., removing cyclic prefix, down converting, serial-to-parallelconversion, analog-to-digital conversion, etc. to effectuate receptionand facilitate subsequent processing.

The BPB 156 may include a fast Fourier transformer (FFT) 160 to receivethe time domain OFDM signal from the receiver 152. The FFT 160 maygenerate a frequency domain OFDM signal and forward the signal to adecoder 164.

At block 308, the decoder 164 may map the physical subcarriers of thephysical carriers to logical subcarriers of the virtual carrieraccording to the mapping scheme provided by mapper 168. In someembodiments, information related to the mapping scheme may betransmitted to the mobile station 108 from the base station 104 in,e.g., downlink (DL) control messages, DL broadcast channel messages,etc.

At block 312, the decoder 164 may decode the logical subcarriers toretrieve the transmitted data. This data may then be output to upperlayers of the mobile station 108 at block 316.

The use of virtual multicarriers for communications between terminalsmay, for example, allow a base station to scale its bandwidth, providesupport for mobile stations having various bandwidths, facilitatedeployment and upgrading of network equipment due, at least in part, tolegacy support, etc. These aspects will be discussed in further detailbelow.

While the described embodiments discuss the base station 104transmitting, and the mobile station 108 receiving, on virtual carriers,other embodiments may additionally/alternatively include the mobilestation 108 transmitting, and the base station 104 receiving, on virtualchannels.

Furthermore, various embodiments of this disclosure describe aligningsubcarriers of adjacent physical carriers of a virtual carrier. As usedherein, subcarrier of adjacent physical carriers may be aligned if thespacing between a subcarrier of a first physical carrier and asubcarrier of a second physical carrier is equal to, or a multiple of, aspacing between adjacent subcarriers within the first (or second)physical carrier. This alignment may reduce, either in part or in total,ISI, which may, in turn, enable use of subcarriers traditional reservedfor guard band. Using these subcarriers for data transmission mayincrease an overall spectrum utilization ratio.

To understand the effect of subcarrier spacing between adjacentcarriers, consider an OFDM signal that is expressed in the time domainas:

$\begin{matrix}{{{y(t)} = {\sum\limits_{k = 0}^{M - 1}\; {{X(k)}^{j\; 2\; \pi \; q_{k}\Delta \; {ft}}}}},{0 \leq t \leq T_{u}},{{T_{u}\Delta \; f} = 1},{{q_{k}\text{:}\mspace{14mu} {int}} \in \left\lbrack {{- \frac{N}{2}},{\frac{N}{2} - 1}} \right\rbrack}} & {{Eq}.\mspace{14mu} 1}\end{matrix}$

and in the frequency domain as:

$\begin{matrix}{{y(t)} = {T_{u}{\sum\limits_{k = 0}^{M - 1}\; {{X(k)}{{Sinc}\left( {\left( {f - {q_{k}\Delta \; f}} \right)T_{u}} \right)}^{{- j}\; 2\; {\pi {({g - {q_{k}\Delta \; f}})}}T_{u}}}}}} & {{Eq}.\mspace{14mu} 2}\end{matrix}$

where M is the number of used subcarriers, T_(u) is useful symbolduration, q_(k) is the position, or index, of the used subcarrier. Eq. 2may be used to calculate the average power spectrum as:

$\begin{matrix}\begin{matrix}{{E\left\{ {{Y(f)}}^{2} \right\}} = {\sigma_{s}^{2}{\sum\limits_{k = 0}^{M - 1}\; {{{Sinc}\left( {\left( {f - {q_{k}\Delta \; f}} \right)T_{u}} \right.}^{2}}}}} \\{{= {\sigma_{s}^{2}{{\sin \left( {\beta \; \pi} \right)}}^{2}{\sum\limits_{k = 0}^{M - 1}\; \frac{1}{{{{\pi \left( {f - {q_{k}\Delta \; f}} \right)}T_{u}}}^{2}}}}},{{Eq}.\mspace{14mu} 4}}\end{matrix} & {{Eq}.\mspace{14mu} 3}\end{matrix}$

where β is a misalignment factor that ranges from 0˜1, and σ_(s) is anexpression of subcarrier energy.

FIG. 4 is a graph illustrating OOBE on two adjacent carriers 404 and 408that have a maximum misalignment factor of 0.5, a 10 MHz bandwidth, 840subcarriers, and no low-pass filter. As can be seen, there is a 0 to −29dB interference signal at guard band subcarriers.

The power of the interference signal from a neighboring carrier may be:

$\begin{matrix}{{10\; {\log \left( {\sigma_{s}^{2}{\sum\limits_{k = 0}^{M - 1}\; \frac{1}{{{{\pi \left( {f - {q_{k}\Delta \; f}} \right)}T_{u}}}^{2}}}} \right)}} + {10\; {\log\left( {\left. {\sin\left( {\beta \; \pi} \right.}^{2} \right).} \right.}}} & {{Eq}.\mspace{14mu} 5}\end{matrix}$

When the subcarriers of adjacent carriers are aligned, as described inaccordance with various embodiments, the alignment factor β=0 and thevalue of the expression “10log(|sin(βπ|²)” of Eq. 5 will go to negativeinfinity. Accordingly, there will be no (or very little) interferencedue to OOBE after the neighboring carriers are well aligned.

The alignment of the subcarriers in adjacent carriers may beaccomplished in a variety of ways. In one embodiment, the IFFT 148 maybe one transformer that utilizes all of the frequency domain samplescorresponding to one virtual channel as one vector input group. In thismanner, the subcarriers across an entire virtual carrier of, e.g., a 20MHz band, may then be equally spaced. The 20 MHz band may be subdividedinto various physical carriers, e.g., two 5 MHz and one 10 MHz carriers.

In another embodiment, the IFFT 148 may include more than onetransformer, e.g., it may include a transformer for each physicalcarrier, with each transformer producing a physical carrier. In thisembodiment, each of the distinct transformers may perform transformfunctions on distinct vector input groups of the frequency domainsamples. When separate transformers are used to independently producephysical carriers, care may be taken to ensure that subcarriers ofadjacent carriers are aligned. In various embodiments, subcarrieralignment may be performed by changing the channel raster to, e.g., 175kHz; by shifting the center frequency of adjacent carriers; and/or tochange the subcarrier spacing to, e.g., 12.5 kHz.

FIG. 5 illustrates various views of a configuration of assignedbandwidth 500 in accordance with embodiments of this disclosure. In thisembodiment, the assigned bandwidth 500 may be a 20 MHz band. The basestation 104 may configure the assigned bandwidth 500 as three physicalcarriers, e.g., physical carrier (PC) 504, PC 508, and PC 512. PCs 504and 508 may be 5 MHz bands, while the PC 512 may be a 10 MHz band. A“physical carrier,” as used herein, may refer to a continuous spectrumof radio frequencies in which at least one mobile station of thewireless communication environment 100 is capable of, and restricted to,communicating with the base station.

The configured PCs may be viewed differently according to thecapabilities of the receiving terminal. A terminal capable ofcommunicating with virtual carriers (hereinafter also referred to as “VCterminal”) may have a VC terminal view 516, while a terminal not able tocommunicate with virtual carriers (hereinafter also referred to as“legacy terminal”) may have a legacy terminal view 520. The base station104 may adapt communications accordingly.

The base station 104 may communicate with a VC terminal having a 20 MHzreceiver by a virtual carrier shown in the VC terminal view 516. Withthe subcarriers of adjacent PCs being aligned, e.g., PC 504 and 508and/or PC 508 and PC 512, the base station 104 may utilize at least someof the edge subcarrier groups, which are reserved as guard bandsubcarriers in prior art systems, for communication. As used herein, “anedge subcarrier group” may be a group of consecutive subcarriers of aparticular PC that includes a subcarrier that is adjacent to subcarriersof an adjacent PC.

Edge subcarrier groups that are adjacent to a PC of a common virtualcarrier may be referred to as interior edge subcarrier groups. In FIG.5, the interior edge subcarrier groups may be groups 524, 528, 532, and536. Given the subcarrier alignment, these interior edge subcarriergroups may be utilized for communications. However, in order to avoidICI with PCs external to the virtual carrier, the groups 540 and 544, orexternal edge subcarrier groups, may be reserved for a guard band.

The base station 104 may communicate with legacy terminal by PC 504,508, or 512 as seen in the legacy terminal view 520. Each legacyterminal will only be capable of receiving data communications on one ofthe PCs. Furthermore, unlike the VC terminals, a legacy terminal willsee the edge subcarrier groups 524, 528, 532, and 536 as being reservedfor a guard band. Accordingly, the legacy terminal will not be able totransmit or receive on subcarriers within these groups.

Communications between the base station 104 and a legacy terminal willnot compromise a contemporaneous communication of the base station 104and a VC terminal that uses the full range of available subcarriers.

FIG. 6 illustrates an OFDM frame 600 in accordance with embodiments ofthe present disclosure. In this embodiment, PCs 604, 608, and 612 areshown. PCs 604 and 608 may each have, e.g., a 10 MHz band, while PC 612may have a 5 MHz band. Each PC may include a preamble 616, edgesubcarriers 620, and a broadcast messaging section 624.

In one embodiment, the base station 104 may encode data onto a firstvirtual carrier (VC1) that includes all three of the PCs 604, 608, and612. In this embodiment, one or more receiving terminals including,e.g., mobile station 108, may have a 25 MHz receiver that accommodatesthe entire range of VC1.

The base station 104 may transmit allocation information on a commonmessaging section 628 to communicate DL and UL allocations to VCterminals. In this embodiment, the base station 104 may use the commonmessaging section 628 to inform the mobile station 108 that downlinkcommunications will be sent to the mobile station 108 at resource 632and that the mobile station 108 may upload information to the basestation 104 at resource 636. As can be seen, the resource 632 mayincorporate edge subcarriers of PCs 604 and 608.

The base station 104 may also encode data onto other virtual carriersthat include various subsets of adjacent PCs. For example, the basestation 104 may encode data onto a second virtual carrier (VC2) thatincludes only PC 604 and PC 608. VC2 may be used for communications withVC terminals having 20 MHz receivers. Hereinafter, a VC terminal havinga 20 MHz receiver may also be referred to as a 20 MHz VC terminal. Inthis embodiment, the base station 104 may communicate, to a particular20 MHz VC terminal, DL allocations at resource 640 and UL allocations atresource 644, which also includes edge subcarrier groups of PC 604 andPC 608.

The base station 104 may additionally/alternatively encode data onto athird virtual carrier (VC1) that includes only PC 608 and PC 612. VC3may be used for communications with 15 MHz VC terminals. In thisembodiment, the base station 104 may communicate, to a particular 15 MHzVC terminal, DL allocations at resource 652 and UL allocations atresource 656, which may include edge subcarrier groups of PC 608 and PC612.

The base station 104 may also use individual PCs to communicate withlegacy terminals. In this embodiment, e.g., 10 MHz legacy terminals maycommunicate with the base station 104 on PC 608. The base station 104may communicate, to a particular 10 MHz legacy terminal, DL allocationsat resource 660 and UL allocations at resource 664. It may be noted thatcommunications between the base station 104 and the legacy terminal maynot use the edge subcarrier groups of the PC 608. However, these sameedge subcarrier groups of PC 608 may be used for communications betweenthe base station 104 and VC terminals without adversely affecting thecommunications with the legacy terminal.

Dividing an assigned bandwidth into various PCs, which may or may nothave the same bandwidths, and utilizing the different PCs in variouscombinations to provide a variety of virtual carriers, may allow basestations endowed with teachings of this disclosure to scalecommunications to terminals configured to operate on any number ofdifferent bandwidths.

In some embodiments, one or more of the PCs of a virtual carrier may beused as a data only pipe. For example, in VC1 control and signalinginformation may be transmitted in PC 608 while the entire spectrum of PC612 is reserved for data communications. However, if a PC is being usedto communicate with a legacy terminal, some amount of control andsignaling information may be desired in said PC.

FIG. 7 illustrates a multicarrier transmission being processed with andwithout reuse of edge subcarriers in accordance with an embodiment ofthe present disclosure. Referring to FIG. 7( a), a virtual carrier,including PCs 704 and 708, may be used for transmissions to a VCterminal and PC 704 may be used for transmissions to a legacy terminal.Each of the PCs 704 and 708 may have 10 MHz bands. Data may bedistributed among the PCs according to a partial usage subchannelization(PUSC) scheme with each PC having 841 subcarriers (not including edgecarrier groups) over a 9.1984 MHz band.

In order to align the two PCs, the center frequency of PC 708 may beshifted by 3.125 KHz, which may result in the center frequencies of thetwo bands being 9.996875 MHz apart. The value of this frequency shift ispurely exemplary and may be adjusted in various embodiments accordingto, e.g., carrier bandwidth, subcarrier spacing, etc.

FIG. 7( b) illustrates subcarriers 712 that represent the 841subcarriers of the PC 704, subcarriers 716 that represent the 73 guardsubcarriers, and subcarriers 720 that correspond to the 841 subcarriersof the PC 708. The legacy terminal may include a 10 MHz band selectionfilter 724 that corresponds to the PC 704.

FIG. 7( c) illustrates data tones that may result from the sampling ofthe subcarriers of FIG. 7( b) when all of the subcarriers, including thesubcarriers 716, are used for data transmission in accordance with anembodiment of the present disclosure. In this embodiment, a commonsampling rate of 11.2 MHz for a 10 MHz carrier is used.

FIG. 7( d) illustrates data tones that may result from the sampling ofthe subcarriers of FIG. 7( b) when the subcarriers 716 are not used fordata transmission in accordance with an embodiment of the presentdisclosure.

As can be seen by FIGS. 7( c) and 7(d), the values of the subcarriersthat are used by the legacy terminal, e.g., subcarriers 712, are notimpacted regardless of whether or not the guard band subcarriers 716 areused.

Therefore, data transmissions to a legacy terminal will not be affected,even when the guard subcarriers of the PC 708 are used and the PC 708 iseffectively shifted closer to the PC 704 due to the alignmentprocessing.

FIG. 8 illustrates how teachings of various embodiments facilitate aflexible deployment and upgrading of network equipment in accordancewith various embodiments of this disclosure. At an initial stage 804, 20MHz of assigned bandwidth may be configured into two 10 MHz bands. Thefirst band may be designated a PC 808 to be used only for communicationswith legacy terminals. The other 10 MHz band may be reserved.

At deployment stage 812, the formally reserved band may be configured asPC 816 to be used only for communications with VC terminals.

At deployment stage 820, the legacy-only PC 808 may be configured as PC824 to be used for communications with legacy and/or VC terminals. Thisstage may be similar to the embodiment discussed with reference to FIG.6.

At deployment stage 828, the legacy/VC PC 824 may be configured as PC832 to be used only for communications with VC terminals. In thisembodiment, the 20 MHz bandwidth may thus be used as two different 10MHz bands or one 20 MHz band for various VC terminals of the wirelesscommunication environment.

FIG. 9 illustrates a computing device 900 capable of implementing a VCterminal in accordance with various embodiments. As illustrated, for theembodiments, computing device 900 includes processor 904, memory 908,and bus 912, coupled to each other as shown. Additionally, computingdevice 900 includes storage 916, and communication interfaces 920, e.g.,a wireless network interface card (WNIC), coupled to each other, and theearlier described elements as shown.

Memory 908 and storage 916 may include in particular, temporal andpersistent copies of coding and mapping logic 924, respectively. Thecoding and mapping logic 924 may include instructions that when accessedby the processor 904 result in the computing device 900 performingencoding/decoding and mapping operations described in conjunction withvarious VC terminals in accordance with embodiments of this disclosure.In particular, these coding and mapping operations may allow a VCterminal, e.g., base station 104 and/or mobile station 108, to transmitand/or receive communications over virtual carriers as described herein.

In various embodiments, the memory 908 may include RAM, dynamic RAM(DRAM), static RAM (SRAM), synchronous DRAM (SDRAM), dual-data rate RAM(DDRRAM), etc.

In various embodiments, the processor 904 may include one or moresingle-core processors, multiple-core processors, controllers,application-specific integrated circuits (ASICs), etc.

In various embodiments, storage 916 may include integrated and/orperipheral storage devices, such as, but not limited to, disks andassociated drives (e.g., magnetic, optical), universal serial bus (USB)storage devices and associated ports, flash memory, read-only memory(ROM), nonvolatile semiconductor devices, etc.

In various embodiments, storage 916 may be a storage resource physicallypart of the computing device 900 or it may be accessible by, but notnecessarily a part of, the computing device 900. For example, thestorage 916 may be accessed by the computing device 900 over a network.

In various embodiments, computing device 900 may have more or lesscomponents, and/or different architectures.

Although certain embodiments have been illustrated and described hereinfor purposes of description of the preferred embodiment, it will beappreciated by those of ordinary skill in the art that a wide variety ofalternate and/or equivalent embodiments or implementations calculated toachieve the same purposes may be substituted for the embodiments shownand described without departing from the scope of the present invention.This application is intended to cover any adaptations or variations ofthe embodiments discussed herein. Therefore, it is manifestly intendedthat embodiments in accordance with the present invention be limitedonly by the claims and the equivalents thereof.

1.-21. (canceled)
 22. A base station comprising: transmit circuitry; andprocess circuitry to control the transmit circuitry to transmit, to awireless communication device, an orthogonal frequency divisionmultiplexing (OFDM) signal that includes allocation information in afirst carrier, the allocation information to indicate, for a wirelesscommunication device, a location of data in a second carrier, wherein aspacing between the first carrier and the second carrier is equal to, ora multiple of, a spacing between adjacent subcarriers of the firstcarrier.
 23. The base station of claim 22, wherein the OFDM signalincludes the data in the second carrier.
 24. The base station of claim22, wherein the first and second carriers comprise adjacent frequencyranges.
 25. The base station of claim 22, further comprising: an inversefast Fourier transformer (IFFT) module to utilize all frequency domainsamples that correspond to the first and second carriers as one vectorinput group.
 26. The base station of claim 22, wherein each of the firstand second carriers have a 5, 10, 15, or 20 megahertz bandwidth.
 27. Thebase station of claim 22, wherein the wireless communication device is afirst wireless communication device and the base station is tocommunicate with a second wireless communication device using only thefirst carrier.
 28. The base station of claim 22, wherein the spacing isbetween a subcarrier of the first plurality of subcarriers and asubcarrier of the second plurality of subcarriers.
 29. The base stationof claim 22, wherein the allocation information is to further indicate alocation of downlink or uplink resources in a third carrier.
 30. One ormore non-transitory, computer-readable media having instructions that,when executed, cause a base station to: encode allocation informationonto a first carrier of an orthogonal frequency division multiplexing(OFDM) signal to facilitate identification, by a wireless communicationdevice, of a location of data in a second carrier, the first carrier toinclude a plurality of first subcarriers and the second carrier toinclude a plurality of second subcarriers, wherein a spacing between asubcarrier of the first plurality of subcarriers and a subcarrier of thesecond plurality of subcarriers is equal to, or a multiple of, a spacingbetween adjacent subcarriers of the plurality of first subcarriers; andtransmit the allocation information to the wireless communicationdevice.
 31. The one or more non-transitory, computer-readable media ofclaim 30, wherein the instructions, when executed, further cause thebase station to encode the data onto the second carrier and transmit thedata to the wireless communication device.
 32. The one or morenon-transitory, computer-readable media of claim 30, wherein the firstand second carriers comprise adjacent frequency ranges.
 33. The one ormore non-transitory, computer-readable media of claim 30, wherein theinstructions, when executed, further cause the base station to: utilizeall frequency domain samples that correspond to the first and secondcarriers as one vector input group in an inverse fast Fourier transform.34. The one or more non-transitory, computer-readable media of claim 30,wherein each of the first and second carriers have a 5, 10, 15, or 20megahertz bandwidth.
 35. The one or more non-transitory,computer-readable media of claim 30, wherein the allocation informationis to further indicate a location of downlink or uplink resources in athird carrier.
 36. The one or more non-transitory, computer-readablemedia of claim 30, wherein the allocation information is to furtherindicate a location of downlink or uplink resources in the firstcarrier.
 37. The one or more non-transitory, computer-readable media ofclaim 30, wherein the second carrier is reserved for data transmissionsand the first carrier is to include control information.
 38. A wirelesscommunication device comprising: receive circuitry to: receive, from abase station, a first orthogonal frequency division multiplexing (OFDM)communication that includes allocation information encoded on a firstcarrier to indicate a location of downlink resources of a second carrierfor the wireless communication device, wherein a spacing between asubcarrier of the first carrier and a subcarrier of the second carriersis equal to, or a multiple of, a spacing between adjacent subcarriers ofthe first carrier; and receive a second OFDM communication that includesthe data encoded on the downlink resources of the second carrier; andprocess circuitry to decode the downlink resources of the second carrierbased on the allocation information.
 39. The wireless communicationdevice of claim 38, wherein the allocation information is to indicateuplink resources in the first or second carrier for the wirelesscommunication device, the processing circuitry is to encode data usingthe uplink resources, and the wireless communication device furthercomprises transmit circuitry to transmit the encoded data using theuplink resources.
 40. The wireless communication device of claim 38,wherein the first and second carriers comprise adjacent frequencyranges.
 41. The wireless communication device of claim 38, wherein thewireless communication device is a mobile phone or computer thatincludes a plurality of antennas.
 42. One or more non-transitory,computer-readable media having instructions that, when executed, cause awireless communication device to: process a first orthogonal frequencydivision multiplexing (OFDM) communication of a first carrier thatincludes a messaging section that has allocation information to indicatedownlink resources in a second carrier are directed to the wirelesscommunication device, wherein a spacing between a subcarrier of thefirst carrier and a subcarrier of the second carriers is equal to, or amultiple of, a spacing between adjacent subcarriers of the firstcarrier; and process a second OFDM communication of the second carrierbased on the allocation information.
 43. The one or more non-transitory,computer-readable media of claim 42, wherein the allocation informationis to indicate uplink resources in the first or second carrier for thewireless communication device and the instructions, when executed, areto further cause the wireless communication device to encode data usingthe uplink resources.
 44. The one or more non-transitory,computer-readable media of claim 42, wherein the first and secondcarriers comprise adjacent frequency ranges.
 45. The one or morenon-transitory, computer-readable media of claim 42, wherein thewireless communication device is a mobile phone or computer thatincludes a plurality of antennas.